Key aspects of the climate are changing faster than expected and if we stay on our current emissions path, we face catastrophe

In 2009, the scientific literature caught up with what top climate scientists have been saying privately for a few years now:

Many of the predicted impacts of human-caused climate change are occurring much faster than anybody expected — particularly ice melt, everywhere you look on the planet.

If we stay anywhere near our current emissions path, we are facing incalculable catastrophes by century's end, including rapid sea level rise, massive wildfires, widespread Dust-Bowlification, large oceanic dead zones, and 9°F warming — much of which could be all but irreversible for centuries. And that's not the worst-case scenario!

The consequences for human health and well being would be extreme.

That's no surprise to anybody who has talked to leading climate scientists in recent years, read my book Hell and High Water (or a number of other books), or followed this blog. Still, it is a scientific reality that I don't think more than 2 people in 100 fully grasp, so I'm going to review here the past year in climate science. I'll focus primarily on the peer-reviewed literature, but also look at some major summary reports.

Let's start with the basics. Heat-trapping greenhouse gases are at unprecedented levels, and the paleoclimate record suggests that even slightly higher levels are untenable:

Measurements of atmospheric CH4 from air samples collected weekly at 46 remote surface sites show that, after a decade of near-zero growth, globally averaged atmospheric methane increased during 2007 and 2008. During 2007, CH4increased by 8.3 ± 0.6 ppb. CH4 mole fractions averaged over polar northern latitudes and the Southern Hemisphere increased more than other zonally averaged regions. In 2008, globally averaged CH4 increased by 4.4 ± 0.6 ppb; the largest increase was in the tropics, while polar northern latitudes did not increase. Satellite and in situ CO observations suggest only a minor contribution to increased CH4from biomass burning. The most likely drivers of the CH4 anomalies observed during 2007 and 2008 are anomalously high temperatures in the Arctic and greater than average precipitation in the tropics. Near-zero CH4 growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.

The anti-science crowd use smoke and mirrors to distract as many people as possible, but the rest of us need to listen to the science and keep our eyes on the prize — reversing greenhouse gas emissions trends as quickly and rapidly as possible.